﻿#region Copyright(c) 2006 ZO, All right reserved.
// -----------------------------------------------------------------------------
// Copyright(c) 2006 ZO, All right reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   1.  Redistribution of source code must retain the above copyright notice,
//       this list of conditions and the following disclaimer.
//   2.  Redistribution in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//   3.  The name of the author may not be used to endorse or promote products
//       derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
// WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
// EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
// OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// -----------------------------------------------------------------------------
#endregion


#region Using directives

using System;
using ZO.SmartCore.Protocols.XMPP.Core;
using ZO.SmartCore.Protocols.XMPP.SASL.Core;
using ZO.SmartCore.Xml;
using ArgumentNullException= ZO.SmartCore.Core.ArgumentNullException;

#endregion

namespace ZO.SmartCore.Protocols.XMPP.SASL.Mechanisms
{
    /// <summary>
    /// HTTP Digest compatible challenge-response scheme based upon MD5. DIGEST-MD5 offers a data security layer.
    /// </summary>
    public class DigestMD5Mechanism : BaseMechanism
    {

        #region Constructors

        #endregion

        #region Destructor

        #endregion

        #region Fields
        private const string MECHANISM_NAME = "DIGEST-MD5";
        private XmppClient Client;

        #endregion

        #region Events

        #endregion

        #region Operators

        #endregion

        #region Properties
        /// <summary>
        /// Get The Name of MechanismName
        /// </summary>
        /// <value></value>
        public override string Name
        {
            get { return MECHANISM_NAME; }
        }

        #endregion

        #region Methods


        /// <summary>
        /// Get the initialized element
        /// </summary>
        /// <returns>Initialized Element</returns>
        public override void Initialize(XmppClient client)
        {
            if (client == null)
            {
                throw new ArgumentNullException("client");
            }

            if (!client.Connected)
            {
                throw new ObjectDisposedException("client");
            }


            Client.Send(new Auth(MECHANISM_NAME));

            this.Client = client;
        }

        /// <summary>
        /// Process the mechanism using specified element and Step Forward
        /// </summary>
        /// <param name="element"></param>
        /// <returns>Processed Element</returns>
        public virtual void Process(Element element)
        {

            if (Client == null)
            {
                throw new ArgumentNullException("client");
            }

            if (!Client.Connected)
            {
                throw new ObjectDisposedException("client");
            }

            if (element.GetType() == typeof(Challenge))
            {
                Challenge challenge1 = element as Challenge;

                Step1 step1 = new Step1(challenge1.ValueAsBase64);

                if (String.IsNullOrEmpty(step1.RspAuth))
                {
                    Step2 s2 = new Step2(step1);

                    Response response1 = new Response(s2.ToString());
                    Client.Send(response1);
                }
                else
                {
                    Client.Send(new Response());
                } // else
            }

        }
        #endregion
    }
}
